The present invention relates to a novel and useful video display system.
Presently, producing video images is chiefly accomplished by the use of a cathode ray tube. Although successful in many aspects of the video technology, cathode ray tubes possess a number of disadvantages in that cathode ray tubes are not easily scaled upwardly in size. This is due to the fact that the weight of the vacuum tube becomes unmanageable with an increase in size, commensurate with a large increase in the cost of manufacture. However, cathode ray tubes produce a very high quality video image, via the fluorescing or phosphor display. Moreover, cathode ray tubes exhibit high brightness, speed, contrast, resolution, and color purity.
Liquid crystal displays (LCD) are lightweight and are capable of producing a video image on a flat screen. Unfortunately, the LCD technology produces a video image of low brightness, low efficiency, and low color purity, which has been described as a "washed-out" look. In addition, the LCD video image possesses low resolution and is not susceptible to wide-angle viewing since the Lambertian effect is not inherent in LCD displays. Moreover, LCDs are slow to display an image and are not cost effective.
Image intensifiers have been proposed such as that found in U.S. Pat. No. 5,029,009 where light is passed through a lens to focus the same onto a substrate having an array of gating electrodes, mounted thereupon. An electrode array and substrate are transparent to light in order to allow the light to pass to a photocathode. Thus, adaptive range gating is accomplished using a single imaging camera.
U.S. Pat. No. 3,864,595 describes an image intensifier tube having a photocathode element which converts incident radiation into corresponding electron images. A microchannel plate multiplies the electron image and sends the same to a phosphor screen to convert the electron image to a corresponding radiation image for viewing. The electron image is easily turned "on" and "off" by selectively applying a gating signal to the photocathode element.
U.S. Pat. No. 4,142,123 describes an image display device utilizing a photocathode, multiplier diodes, and an anode electrode in a cathode luminescent screen. The anode electrode is constructed of a material which exhibits slow fluorescence to permit emission of light energy after excitation has ceased. Electrons created in the discharge strike of the anode electrode are directed to the photocathode where they are converted into free electrons. Rapid initiation of subsequent electrical discharges is ensured by such free electrons.
U.S. Pat. No. 5,160,565 describes an image intensifier utilizing a fiber optic bundle which receives an image at one end and produces an intensified image at the other end of the bundle.
U.S. Pat. No. 3,742,285 teaches an image intensifier display system where a display tube having a fiber optic input window includes an electron emitting surface. Electrons impinge on a display window of larger diameter having a phosphor coated surface to provide a magnified image of a scene being viewed.
U.S. Pat. No. 4,694,171 describes an electron microscope imaging system which employs an image intensifier which receives light emitted from an image that is excited by an electron beam.
U.S. Pat. No. 4,213,055 shows an image intensifier tube which utilizes an entrance detection screen mounted in an envelope adjacent to an entrance window. An electron optical system also mounted in the envelope images electrons which pass to an exit screen in the envelope, resulting in a viewable video image.
U.S. Pat. No. 4,974,089 teaches a television camera in which an index rod lens is employed to relay a light image from an image intensifier to a filter which is coupled to a focal plane array assembly.
U.S. Pat. No. 3,757,351 illustrates an electrostatic printing system where light is reflected from a document, passed through a lens, and intensified by a container having a photocathode placed on a glass substrate. The cathode converts the photon image to an electron image which then passes through a microchannel plate and sends the image to a dielectric target in the form of an electro static charge. The electro static charge is then used to print a document.
A video display system which is capable of intensifying an image from a video source accurately and efficiently to produce a video display of very high quality would be a notable advance in the electronics field.